1. Technical Field
The invention relates to a light source module, and particularly relates to a light source module adapted for a display device.
2. Related Art
In recent years, along with enhancement of light-emitting efficiency and prolonging of service life of light-emitting diodes (LEDs), and due to characteristics and advantages of low power consumption, low pollution, high efficiency, high response speed, small volume, light weight and capable of being disposed on various surfaces, the LEDs are widely applied in various optical fields. Generally, the LEDs can be applied to various illumination devices and various planar displays in daily life, for example, liquid crystal displays (LCDs).
Taking the application of the LED in the LCD domain as an example, a backlight module of the LCD is a planar light source, and a basic operation principle thereof is to convert valid light of a linear light source or a point light source into a planar light source with high brightness and good uniformity. Generally, based on different light source positions, the light source modules are grouped into side incident type light source modules and direct type light source modules, wherein since a structure of the direct type backlight module is simple and a plurality sets of light sources can be adopted, the direct type backlight module may provide higher brightness and luminance, so that it is generally used in electronic products having a large size LCD.
Further, in the current direct type backlight module, the number of the used LEDs is decreased or a height of light cavity is decreased by configuring a secondary optical lens; however a product cost is increased. On the other hand, regarding a direct type backlight module without using the secondary optical lens, it has a thicker light cavity, or more LEDs have to be configured, so that system reliability is decreased. Moreover, regarding another direct type backlight module without using the secondary optical lens, it is mainly composed of LEDs, a reflective lampshade, a diffusion plate, and a bottom reflective sheet, in which the reflective lampshade reflects a light beam come from the LEDs to the bottom reflective sheet, and the bottom reflective sheet reflects the light beam to the diffusion plate for emitting light, such that the above direct type backlight module may have a lower cost and thinner thickness to achieve a great advantage. However, a brightness of the backlight module is determined by a brightness of a center point thereof, so that under a premise that a limited number of the LEDs are used, it is important to improve the brightness of the center point while considering light-emitting uniformity and front of screen (FOS) performance.
Taiwan Patent No. I410714B discloses a side incident type light source module including a light guide plate and a plurality of LED light sources. Taiwan Patent No. M444487U1 discloses a bar-shape lampshade, where one side of the bar-shape lampshade is recessed to form a reflective trough. Taiwan Patent Publication No. 200907229A discloses an LED device disposed in a reflective lampshade. Taiwan Patent No. I386685B discloses a casing including an extending reflective portion. China Patent No. CN100389349C discloses a reflective plate disposed on a substrate of a casing.